Fluoro substituted cycloalkanoindoles, compositions containing such compounds and methods of treatment

ABSTRACT

Fluoro substituted cycloalkanoindole derivatives are antagonists of prostaglandins, and as such are useful for the treatment of prostaglandin mediated diseases.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the National Stage of International Application No.PCT/CA03/00084, filed 22 Jan. 2003 which claims the benefit under 35U.S.C. 119(e) of U.S. Provisional Application No. 60/351384, filed 24Jan. 2002.

BACKGROUND OF THE INVENTION

The present invention relates to compounds and methods for treatingprostaglandin mediated diseases, and certain pharmaceutical compositionsthereof. More particularly, the compounds of the invention arestructurally different from steroids, antihistamines or adrenergicagonists, and are antagonists of the nasal and pulmonary congestioneffects of D-type prostaglandins.

Two review articles describe the characterization and therapeuticrelevance of the prostanoid receptors as well as the most commonly usedselective agonists and antagonists: Eicosanoids: From Biotechnology toTherapeutic Applications, Folco, Samuelsson, Maclouf, and Velo eds,Plenum Press, New York, 1996, chap. 14, 137-154 and Journal of LipidMediators and Cell Signalling, 1996, 14, 83-87. An article from T. Tsuriet al. published in 1997 in Journal of Medicinal Chemistry, vol 40,pp.3504-3507 states that “PGD2 is considered to be an important mediatorin various allergic diseases such allergic rhinitis, atopic asthma,allergic conjunctivitis and atopic dermatitis.” More recently, anarticle by Matsuoka et al. in Science (2000), 287:2013-7, describes PGD2as being a key mediator in allergic asthma. In addition, patents such asU.S. Pat. No. 4,808,608 refer to prostaglandin antagonists as useful inthe treatment of allergic diseases, and explicitly allergic asthma. PGD2antagonists are described in, for example, European Patent Application837,052 and PCT Application WO98/25919, as well as WO99/62555.

U.S. Pat. No. 4,808,608 discloses tetrahydrocarbazole-1-alkanoic acidderivatives as prostaglandin antagonists.

PCT Application WO0179169 discloses PGD2 antagonists having the formula:

European Patent Application 468,785 discloses the compound4-[(4-chlorophenyl(methyl]-1,2,3,4-tetrahydro-7-(2-quinolinylmethoxy)-cyclopent[b]indole-3-aceticacid, which is a species of a genus said to be leukotriene biosynthesisinhibitors.

U.S. Pat. No. 3,535,326 discloses antiphlogistic compounds of theformula:

SUMMARY OF THE INVENTION

The present invention provides novel compounds which are prostaglandinreceptor antagonists; more particularly, they are prostaglandin D2receptor (DP receptor) antagonists. Compounds of the present inventionare useful for the treatment of various prostaglandin-mediated diseasesand disorders; accordingly the present invention provides a method forthe treatment of prostaglandin-mediated diseases using the novelcompounds described herein, as well as pharmaceutical compositionscontaining them.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to compounds of formula I:

and pharmaceutically acceptable salts thereof, wherein n is 0 or 1; m is1, 2 or 3; R₁ is H, C₁-C₃ alkyl, halogenated C₁-C₃ alkyl or cyclopropyl;R₂ is 4-chlorophenyl or 2,4,6-trichlorophenyl.

In one embodiment of formula I are compounds wherein n is 0.

In another embodiment of formula I are compounds wherein n is 1.

In another embodiment of formula I are compounds wherein m is 1.

In another embodiment of formula I are compounds wherein m is 2.

In another embodiment of formula I are compounds wherein R₁ is H.

In another embodiment of formula I are compounds wherein R₁ is CH₃.

In another embodiment of formula I are compounds wherein R₂ is4-chlorophenyl.

In another embodiment of formula I are compounds wherein R₂ is2,4,6-trichlorophenyl.

In another embodiment of formula I are compounds having thestereoconfiguration shown below (i.e. the chiral center has the Rconfiguration):

In another aspect of the present invention there is providedpharmaceutical compositions comprising a compound of formula I, and apharmaceutically acceptable carrier.

In one embodiment, the pharmaceutical compositions further comprises asecond active ingredient selected from an antihistamine, a leukotrieneantagonist, leukotriene biosynthesis inhibitor, prostaglandin receptorantagonists or biosynthesis inhibitors, corticosteroids, cytokinemodulators, anti-IgE, anti-cholinergics or NSAIDS.

In another aspect of the present invention there is provided a methodfor the treatment or prevention of prostaglandin D2 mediated diseaseswhich comprises administering to a patient in need of treatment atherapeutically effective amount of a compound of formula I.

In one embodiment of the invention is a method of treating or preventinga prostaglandin D2 mediated disease comprising administering to amammalian patient in need of such treatment a compound of formula I inan amount which is effective for treating or preventing a prostaglandinD2 mediated disease, wherein the prostaglandin mediated disease is nasalcongestion, rhinitis including seasonal allergic rhinitis and perennialallergic rhinitis, and asthma including allergic asthma.

In another embodiment of the present invention is a method for thetreatment of nasal congestion in a patient in need of such treatmentwhich comprises administering to said patient a therapeuticallyeffective amount of a compound of formula I.

In yet another embodiment of the present invention is a method for thetreatment of asthma, including allergic asthma, in a patient in need ofsuch treatment which comprises administering to said patient atherapeutically effective amount of a compound of formula I.

In yet another embodiment of the present invention is a method for thetreatment of allergic rhinitis (seasonal and perennial) in a patient inneed of such treatment which comprises administering to said patient atherapeutically effective amount of a compound of formula I.

The numbering of the core tricyclic ring system when m is 1 is as shownbelow:

The numbering of the core tricyclic ring system when m is 2 is as shownbelow:

Optical Isomers—Diastereomers—Tautomers

Compounds of formula I contain one or more asymmetric centers and canthus occur as racemates and racemic mixtures, single enantiomers,diastereomeric mixtures and individual diastereomers. The presentinvention is meant to comprehend all such isomeric forms of thecompounds of formula I.

Some of the compounds described herein may exist with different pointsof attachment of hydrogen, referred to as tautomers. Such an example maybe a ketone and its enol form known as keto-enol tautomers. Theindividual tautomers as well as mixture thereof are encompassed withcompounds of formula I.

Compounds of formula I may be separated into diastereoisomeric pairs ofenantiomers by, for example, fractional crystallization from a suitablesolvent, for example methanol or ethyl acetate or a mixture thereof. Thepair of enantiomers thus obtained may be separated into individualstereoisomers by conventional means, for example by the use of anoptically active acid or base as a resolving agent, or by chiralseparation techniques such as separation by HPLC using a chiral column.

Alternatively, any enantiomer of a compound of the general formula I orIa may be obtained by stereospecific synthesis using optically purestarting materials or reagents of known configuration.

Salts

The term “pharmaceutically acceptable salts” refers to salts preparedfrom pharmaceutically acceptable non-toxic bases including inorganicbases and organic bases. Salts derived from inorganic bases includealuminum, ammonium, calcium, copper, ferric, ferrous, lithium,magnesium, manganic salts, manganous, potassium, sodium, zinc, and thelike. Particularly preferred are the ammonium, calcium, magnesium,potassium, and sodium salts. Salts derived from pharmaceuticallyacceptable organic non-toxic bases include salts of primary, secondary,and tertiary amines, substituted amines including naturally occurringsubstituted amines, cyclic amines, and basic ion exchange resins, suchas arginine, betaine, caffeine, choline, N,N′-dibenzylethylenediamine,diethylamine, 2-diethylaminoethanol, 2-dimethylaminoethanol,ethanolamine, ethylenediamine, N-ethyl-morpholine, N-ethylpiperidine,glucamine, glucosamine, histidine, hydrabamine, isopropylamine, lysine,methylglucamine, morpholine, piperazine, piperidine, polyamine resins,procaine, purines, theobromine, triethylamine, trimethylamine,tripropylamine, tromethamine, and the like.

When the compound of the present invention is basic, salts may beprepared from pharmaceutically acceptable non-toxic acids, includinginorganic and organic acids. Such acids include acetic, benzenesulfonic,benzoic, camphorsulfonic, citric, ethanesulfonic, fumaric, gluconic,glutamic, hydrobromic, hydrochloric, isethionic, lactic, maleic, malic,mandelic, methanesulfonic, mucic, nitric, pamoic, pantothenic,phosphoric, succinic, sulfuric, tartaric, p-toluenesulfonic acid, andthe like. Particularly preferred are citric, hydrobromic, hydrochloric,maleic, phosphoric, sulfuric, and tartaric acids.

It will be understood that, unless otherwise specified, references tothe compound of formula I are meant to also include the pharmaceuticallyacceptable salts.

Utilities

Compounds of formula I are antagonists of prostaglandin D2. The abilityof compounds of formula I to interact with prostaglandin D2 receptormakes them useful for preventing or reversing undesirable symptomscaused by prostaglandins in a mammalian, especially human subject. Theantagonism of the actions of prostaglandin D2 indicates that thecompounds and pharmaceutical compositions thereof are useful to treat,prevent, or ameliorate in mammals and especially in humans: respiratoryconditions, allergic conditions, pain, inflammatory conditions, mucussecretion disorders, bone disorders, sleep disorders, fertilitydisorders, blood coagulation disorders, trouble of the vision as well asimmune and autoimmune diseases. In addition, such a compound may inhibitcellular neoplastic transformations and metastic tumor growth and hencecan be used in the treatment of cancer. Compounds of formula I may alsobe of use in the treatment and/or prevention prostaglandin D2 mediatedproliferation disorders such as may occur in diabetic retinopathy andtumor angiogenesis. Compounds of formula I may also inhibitprostanoid-induced smooth muscle contraction by antagonizing contractileprostanoids or mimicking relaxing prostanoids and hence may be use inthe treatment of dysmenorrhea, premature labor and eosinophil relateddisorders.

Accordingly, another aspect of the invention provides a method oftreating or preventing a prostaglandin D2 mediated disease comprisingadministering to a mammalian patient in need of such treatment acompound of formula I in an amount which is effective for treating orpreventing said prostaglandin D2 mediated disease. Prostaglandin D2mediated diseases include, but are not limited to, allergic rhinitis,nasal congestion, rhinorrhea, perennial rhinitis, nasal inflammation,asthma including allergic asthma, chronic obstructive pulmonary diseasesand other forms of lung inflammation; pulmonary hypotension; sleepdisorders and sleep-wake cycle disorders; prostanoid-induced smoothmuscle contraction associated with dysmenorrhea and premature labor;eosinophil related disorders; thrombosis; glaucoma and vision disorders;occlusive vascular diseases, such as for example atherosclerosis;congestive heart failure; diseases or conditions requiring a treatmentof anti-coagulation such as post-injury or post surgery treatment;rheumatoid arthritis and other inflammatory diseases; gangrene;Raynaud's disease; mucus secretion disorders including cytoprotection;pain and migraine; diseases requiring control of bone formation andresorption such as for example osteoporosis; shock; thermal regulationincluding fever; rejection in organ transplant and by-pass surgery, andimmune disorders or conditions in which immunoregulation is desirable.More particularly the disease to be treated is one mediated byprostaglandin D2 such as nasal congestion, allergic rhinitis, pulmonarycongestion, and asthma including allergic asthma.

Dose Ranges

The magnitude of prophylactic or therapeutic dose of a compound offormula I will, of course, vary with the nature and the severity of thecondition to be treated and with the particular compound of formula Iand its route of administration. It will also vary according to avariety of factors including the age, weight, general health, sex, diet,time of administration, rate of excretion, drug combination and responseof the individual patient. In general, the daily dose from about 0.001mg to about 100 mg per kg body weight of a mammal, preferably 0.01 mg toabout 10 mg per kg. On the other hand, it may be necessary to usedosages outside these limits in some cases.

The amount of active ingredient that may be combined with the carriermaterials to produce a single dosage form will vary depending upon thehost treated and the particular mode of administration. For example, aformulation intended for the oral administration of humans may containfrom 0.05 mg to 5 g of active agent compounded with an appropriate andconvenient amount of carrier material which may vary from about 5 toabout 99.95 percent of the total composition. Dosage unit forms willgenerally contain between from about 0.1 mg to about 0.4 g of an activeingredient, typically 0.5 mg, 1 mg, 2 mg, 5 mg, 10 mg, 25 mg, 50 mg, 100mg, 200 mg, or 400 mg.

Pharmaceutical Compositions

Another aspect of the present invention provides pharmaceuticalcompositions comprising a compound of formula I with a pharmaceuticallyacceptable carrier. The term “composition”, as in pharmaceuticalcomposition, is intended to encompass a product comprising the activeingredient(s), and the inert ingredient(s) (pharmaceutically acceptableexcipients) that make up the carrier, as well as any product whichresults, directly or indirectly, from combination, complexation oraggregation of any two or more of the ingredients, or from dissociationof one or more of the ingredients, or from other types of reactions orinteractions of one or more of the ingredients. Accordingly, thepharmaceutical compositions of the present invention encompass anycomposition made by admixing a compound of Formula I, additional activeingredient(s), and pharmaceutically acceptable excipients.

For the treatment of any of the prostanoid mediated diseases compoundsof formula I may be administered orally, by inhalation spray, topically,parenterally or rectally in dosage unit formulations containingconventional non-toxic pharmaceutically acceptable carriers, adjuvantsand vehicles. The term parenteral as used herein includes subcutaneousinjections, intravenous, intramuscular, intrastemal injection orinfusion techniques. In addition to the treatment of warm-bloodedanimals such as mice, rats, horses, cattle, sheep, dogs, cats, etc., thecompound of the invention is effective in the treatment of humans.

The pharmaceutical compositions containing the active ingredient may bein a form suitable for oral use, for example, as tablets, troches,lozenges, aqueous or oily suspensions, dispersible powders or granules,emulsions, hard or soft capsules, or syrups or elixirs. Compositionsintended for oral use may be prepared according to any method known tothe art for the manufacture of pharmaceutical compositions and suchcompositions may contain one or more agents selected from the groupconsisting of sweetening agents, flavouring agents, colouring agents andpreserving agents in order to provide pharmaceutically elegant andpalatable preparations. Tablets contain the active ingredient inadmixture with non-toxic pharmaceutically acceptable excipients whichare suitable for the manufacture of tablets. These excipients may be forexample, inert diluents, such as calcium carbonate, sodium carbonate,lactose, calcium phosphate or sodium phosphate; granulating anddisintegrating agents, for example, corn starch, or alginic acid;binding agents, for example starch, gelatin or acacia, and lubricatingagents, for example, magnesium stearate, stearic acid or talc. Thetablets may be uncoated or they may be coated by known techniques todelay disintegration and absorption in the gastrointestinal tract andthereby provide a sustained action over a longer period. For example, atime delay material such as glyceryl monostearate or glyceryl distearatemay be employed. They may also be coated by the technique described inthe U.S. Pat. Nos. 4,256,108; 4,166,452; and 4,265,874 to form osmotictherapeutic tablets for control release.

Formulations for oral use may also be presented as hard gelatin capsuleswherein the active ingredient is mixed with an inert solid diluent, forexample, calcium carbonate, calcium phosphate or kaolin, or as softgelatin capsules wherein the active ingredients is mixed withwater-miscible solvents such as propylene glycol, PEGs and ethanol, oran oil medium, for example peanut oil, liquid paraffin, or olive oil.

Aqueous suspensions contain the active material in admixture withexcipients suitable for the manufacture of aqueous suspensions. Suchexcipients are suspending agents, for example sodiumcarboxymethylcellulose, methylcellulose, hydroxypropyl methylcellulose,sodium alginate, polyvinylpyrrolidone, gum tragacanth and gum acacia;dispersing or wetting agents may be a naturally-occurring phosphatide,for example lecithin, or condensation products of an alkylene oxide withfatty acids, for example polyoxyethylene stearate, or condensationproducts of ethylene oxide with long chain aliphatic alcohols, forexample heptadecaethyleneoxycetanol, or condensation products ofethylene oxide with partial esters derived from fatty acids and ahexitol such as polyoxyethylene sorbitol monooleate, or condensationproducts of ethylene oxide with partial esters derived from fatty acidsand hexitol anhydrides, for example polyethylene sorbitan monooleate.The aqueous suspensions may also contain one or more preservatives, forexample ethyl, or n-propyl, p-hydroxybenzoate, one or more colouringagents, one or more flavouring agents, and one or more sweeteningagents, such as sucrose, saccharin or aspartame.

Oily suspensions may be formulated by suspending the active ingredientin a vegetable oil, for example arachis oil, olive oil, sesame oil orcoconut oil, or in mineral oil such as liquid paraffin. The oilysuspensions may contain a thickening agent, for example beeswax, hardparaffin or cetyl alcohol. Sweetening agents such as those set forthabove, and flavouring agents may be added to provide a palatable oralpreparation. These compositions may be preserved by the addition of ananti-oxidant such as ascorbic acid.

Dispersible powders and granules suitable for preparation of an aqueoussuspension by the addition of water provide the active ingredient inadmixture with a dispersing or wetting agent, suspending agent and oneor more preservatives. Suitable dispersing or wetting agents andsuspending agents are exemplified by those already mentioned above.Additional excipients, for example sweetening, flavouring and colouringagents, may also be present.

The pharmaceutical compositions of the invention may also be in the formof an oil-in-water emulsion. The oily phase may be a vegetable oil, forexample olive oil or arachis oil, or a mineral oil, for example liquidparaffin or mixtures of these. Suitable emulsifying agents may benaturally-occurring phosphatides, for example soy bean, lecithin, andesters or partial esters derived from fatty acids and hexitolanhydrides, for example sorbitan monooleate, and condensation productsof the said partial esters with ethylene oxide, for examplepolyoxyethylene sorbitan monooleate. The emulsions may also containsweetening and flavouring agents.

Syrups and elixirs may be formulated with sweetening agents, for exampleglycerol, propylene glycol, sorbitol or sucrose. Such formulations mayalso contain a demulcent, a preservative and flavouring and colouringagents. The pharmaceutical compositions may be in the form of a sterileinjectable aqueous or oleagenous suspension. This suspension may beformulated according to the known art using those suitable dispersing orwetting agents and suspending agents which have been mentioned above.The sterile injectable preparation may also be a sterile injectablesolution or suspension in a non-toxic parenterally-acceptable diluent orsolvent, for example as a solution in 1,3-butane diol. Among theacceptable vehicles and solvents that may be employed are water,Ringer's solution and isotonic sodium chloride solution. Cosolvents suchas ethanol, propylene glycol or polyethylene glycols may also be used.In addition, sterile, fixed oils are conventionally employed as asolvent or suspending medium. For this purpose any bland fixed oil maybe employed including synthetic mono- or diglycerides. In addition,fatty acids such as oleic acid find use in the preparation ofinjectables.

Compounds of formula I may also be administered in the form ofsuppositories for rectal administration of the drug. These compositionscan be prepared by mixing the drug with a suitable non-irritatingexcipient which is solid at ambient temperatures but liquid at therectal temperature and will therefore melt in the rectum to release thedrug. Such materials are cocoa butter and polyethylene glycols.

For topical use, creams, ointments, gels, solutions or suspensions,etc., containing the compound of formula I are employed. (For purposesof this application, topical application shall include mouth washes andgargles.) Topical formulations may generally be comprised of apharmaceutical carrier, cosolvent, emulsifier, penetration enhancer,preservative system, and emollient.

Combinations with Other Drugs

For the treatment and prevention of prostaglandin mediated diseases,compound of formula I may be co-administered with other therapeuticagents. Thus in another aspect the present invention providespharmaceutical compositions for treating prostaglandin D2 mediateddiseases comprising a therapeutically effective amount of a compound offormula I and one or more other therapeutic agents. Suitable therapeuticagents for combination therapy with a compound of formula I include: (1)a prostaglandin receptor antagonist; (2) a corticosteroid such astriamcinolone acetonide; (3) a β-agonist such as salmeterol, formoterol,terbutaline, metaproterenol, albuterol and the like; (4) a leukotrienemodifier, such as a leukotriene antagonist or a lipooxygenase inhibitorsuch as montelukast, zafirlukast, pranlukast, or zileuton; (5) anantihistamine (histamine H1 antagonist) such as bromopheniramine,chlorpheniramine, dexchlorpheniramine, triprolidine, clemastine,diphenhydramine, diphenylpyraline, tripelennamine, hydroxyzine,methdilazine, promethazine, trimeprazine, azatadine, cyproheptadine,antazoline, pheniramine, pyrilamine, astemizole, norastemizole,terfenadine, loratadine, cetirizine, levocetirizine, fexofenadine,desloratadine, and the like; (6) a decongestant including phenylephrine,phenylpropanolamine, pseudophedrine, oxymetazoline, ephinephrine,naphazoline, xylometazoline, propylhexedrine, or levo-desoxyephedrine;(7) an antiitussive including codeine, hydrocodone, caramiphen,carbetapentane, or dextramethorphan; (8) another prostaglandin ligandincluding prostaglandin F agonist such as latanoprost; misoprostol,enprostil, rioprostil, ornoprostol or rosaprostol; (9) a diuretic; (10)non-steroidal antiinflammatory agents (NSAIDs) such as propionic acidderivatives (alminoprofen, benoxaprofen, bucloxic acid, carprofen,fenbufen, fenoprofen, fluprofen, flurbiprofen, ibuprofen, indoprofen,ketoprofen, miroprofen, naproxen, oxaprozin, pirprofen, pranoprofen,suprofen, tiaprofenic acid, and tioxaprofen), acetic acid derivatives(indomethacin, acemetacin, alclofenac, clidanac, diclofenac,fenclofenac, fenclozic acid, fentiazac, furofenac, ibufenac, isoxepac,oxpinac, sulindac, tiopinac, tolmetin, zidometacin, and zomepirac),fenamic acid derivatives (flufenamic acid, meclofenamic acid, mefenamicacid, niflumic acid and tolfenamic acid), biphenylcarboxylic acidderivatives (diflunisal and flufenisal), oxicams (isoxicam, piroxicam,sudoxicam and tenoxican), salicylates (acetyl salicylic acid,sulfasalazine) and the pyrazolones (apazone, bezpiperylon, feprazone,mofebutazone, oxyphenbutazone, phenylbutazone); (11) cyclooxygenase-2(COX-2) inhibitors such as celecoxib and rofecoxib, etoricoxib andvaldecoxib; (12) inhibitors of phosphodiesterase type IV (PDE-IV) e.g.Ariflo, roflumilast; (13) antagonists of the chemokine receptors,especially CCR-1, CCR-2, and CCR-3; (14) cholesterol lowering agentssuch as HMG-CoA reductase inhibitors (lovastatin, simvastatin andpravastatin, fluvastatin, atorvastatin, and other statins), sequestrants(cholestyramine and colestipol), nicotinic acid, fenofibric acidderivatives (gemfibrozil, clofibrat, fenofibrate and benzafibrate), andprobucol; (15) anti-diabetic agents such as insulin, sulfonylureas,biguanides (metforrnin), α-glucosidase inhibitors (acarbose) andglitazones (troglitazone, pioglitazone, englitazone, rosiglitazone andthe like); (16) preparations of interferon beta (interferon beta-1a,interferon beta-1b); (17) anticholinergic agents such as muscarinicantagonists (ipratropium bromide and tiotropium bromide), as well asselective muscarinic M3 antagonists; (18) steroids such asbeclomethasone, methylprednisolone, betamethasone, prednisone,dexamethasone, and hydrocortisone; (19) triptans commonly used for thetreatment of migraine such as sumitriptan and rizatriptan; (20)alendronate and other treatments for osteoporosis; (21) other compoundssuch as 5-aminosalicylic acid and prodrugs thereof, antimetabolites suchas azathioprine and 6-mercaptopurine, cytotoxic cancer chemotherapeuticagents, bradykinin (BK2 or BK1) antagonists, TP receptor antagonistssuch as seratrodast, neurokinin antagonists (NK1/NK2), VLA-4 antagonistssuch as those described in U.S. Pat. No. 5,510,332, WO97/03094,WO97/02289, WO96/40781, WO96/22966, WO96/20216, WO96/01644, WO96/06108,WO95/15973 and WO96/31206.

In addition, the invention encompasses a method of treatingprostaglandin D2 mediated diseases comprising: administering to apatient in need of such treatment a therapeutically effective amount ofthe compound of formula I, co-administered with one or more of suchingredients as listed immediately above. The amounts of activeingredients may be those commonly used for each active ingredient whenit is administered alone, or in some instances the combination of activeingredients may result in lower dosage for one or more of the activeingredients.

Abbreviations Used Ac acetyl AcOH acetic acid DDQ2,3-dichloro-5,6-dicyano-1,4-benzoquinone DMF dimethylformamide eq.equivalent(s) Et ethyl EtOAc ethyl acetate EtOH ethanol HPLC highpressure liquid chromatography IPA isopropyl alcohol IPAc isopropylacetate Me methyl MeOH methanol MHz megahertz MTBE methyl t-butyl etherNMP N-methyl-2-pyrrolidinone NMR nuclear magnetic resonance THFtetrahydrofuran TLC thin-layer chromatography

METHODS OF SYNTHESIS

Compounds of Formula I of the present invention can be preparedaccording to the synthetic routes outlined in Schemes 1 to 5 and byfollowing the methods described herein.

Intermediate compounds of Formula IV may be prepared by the methodpresented in Scheme 1 from an appropriately substituted phenyl hydrazineII. Reaction of II with an appropriate cycloalkanone III (where R isester group such as an alkyl group) under Fisher Indole or similarconditions gives IV

Compounds of Formula IV may alternatively be prepared by the methodpresented in Scheme 2 from an appropriately substituted aniline V.Condensation of V with an appropriate cycloalkanone III followed by thecyclization under Heck or similar metal catalysis conditions leads toindole IV

Compounds of Formula III may be prepared by the method presented inScheme 3 from an appropriately substituted silyl enol ether VI or anappropriately substituted enamine VII. Addition of an appropriateelectrophile such as Y—CH₂CO₂R (wherein Y represents a halogen or aleaving group) in the presence of a base such as an alkyl lithium or aLewis acid such as silver trifluoroacetate with the silyl enol ether VIgives the cycloalkanone III. The compound of formula III mayalternatively be prepared from the addition of Y—CH₂CO₂R on anappropriately substituted enamine VII under Stork Enamine or similarconditions

Intermediate compounds of Formula VIII may be prepared by the methodpresented in Scheme 4 from an appropriately substituted indole IV.Bromination of IV may be accomplished with bromine or a brominatingagent such as pyridium tribromide, under basic condition in a polarsolvent, for example, by carrying out the reaction in pyridine or in asolvent such as dichloromethane in the presence of pyridine followed bythe mono reduction of a dibromo intermediate under acid and reducingmetal conditions to generate the bromoindole VIII

Compounds of Formula I may be prepared by the method presented in Scheme5 from an appropriately substituted bromoindole VIII. Alkylation of VIIIwith the appropriate electrophile such as (R₁)(R₂)CH—Y in the presenceof a base and in a suitable solvent such as DMF gives N-alkylated indoleIX. Coupling of IX with a methanesulfinate such as sodiummethanesulfinate in the presence of Cu(I) salts leads to compounds offormula I, following ester hydrolysis. The bromoindole acid (IX, R═H)may alternatively first react with a suitable metallation agent, such asn-BuLi, followed by trapping with an electrophile such as methyldisulfide to give the corresponding methyl sulfide, which upon oxidationwith for example hydrogen peroxide/sodium tungstate provides compoundIA. The steps of alkylation of the bromoindole VIII followed bysulfonylation may also be reversed; thus sulfonylation of thebromoindole VIII provides the compound X, which is alkylated usingsimilar conditions as described before or by using Mitsunobu reactionconditions to provide compound of formula IA following ester hydrolysis.

Compound IB may be prepared from protected IA, for example an ester ofIA, by oxidation using a suitable oxidant followed by hydrolysis, asillustrated in Scheme 6.

Alternatively, IB can be prepared, as illustrated in Scheme 7, byoxidizing IX with a suitable oxidizing agent, such as DDQ, followed bymethylsulfonylation as described in Scheme 5 follwed by hydrolysis.

Assays for Determining Biological Activity

Compounds of formula I can be tested using the following assays todetermine their prostanoid antagonist or agonist activity in vitro andin vivo and their selectivity. The prostaglandin receptor activitiesdemonstrated are DP, EP₁, EP₂, EP₃, EP₄, FP, IP and TP.

Stable Expression of Prostanoid Receptors in the Human Embryonic Kidney(HEK) 293(ebna) Cell Line

Prostanoid receptor cDNAs corresponding to full length coding sequencesare subcloned into the appropriate sites of mammalian expression vectorsand transfected into HEK 293(ebna) cells. HEK 293(ebna) cells expressingthe individual cDNAs are grown under selection and individual coloniesare isolated after 2-3 weeks of growth using the cloning ring method andsubsequently expanded into clonal cell lines.

Prostanoid Receptor Binding Assays

HEK 293(ebna) cells are maintained in culture, harvested and membranesare prepared by differential centrifugation, following lysis of thecells in the presence of protease inhibitors, for use in receptorbinding assays. Prostanoid receptor binding assays are performed in 10mM MES/KOH (pH 6.0) (EPs, FP and TP) or 10 mM HEPES/KOH (pH 7.4) (DP andIP), containing 1 mM EDTA, 10 mM divalent cation and the appropriateradioligand. The reaction is initiated by addition of membrane protein.Ligands are added in dimethylsulfoxide which is kept constant at 1%(v/v) in all incubations. Non-specific binding is determined in thepresence of 1 μM of the corresponding non-radioactive prostanoid.Incubations are conducted for 60 min at room temperature or 30° C. andterminated by rapid filtration. Specific binding is calculated bysubtracting non specific binding from total binding. The residualspecific binding at each ligand concentration is calculated andexpressed as a function of ligand concentration in order to constructsigmoidal concentration-response curves for determination of ligandaffinity.

Prostanoid Receptor Agonist and Antagonist Assays

Whole cell second messenger assays measuring stimulation (EP₂, EP₄, DPand IP in HEK 293(ebna) cells) or inhibition (EP₃ in humanerythroleukemia (HEL) cells) of intracellular cAMP accumulation ormobilization of intracellular calcium (EP₁, FP and TP in HEK 293(ebna)cells stably transfected with apo-aequorin) are performed to determinewhether receptor ligands are agonists or antagonists. For cAMP assays,cells are harvested and resuspended in HBSS containing 25 mM HEPES, pH7.4. Incubations contain 100 μM RO-20174 (phosphodiesterase type IVinhibitor, available from Biomol) and, in the case of the EP₃ inhibitionassay only, 15 μM forskolin to stimulate cAMP production. Samples areincubated at 37° C. for 10 min, the reaction is terminated and cAMPlevels are then measured. For calcium mobilization assays, cells arecharged with the co-factors reduced glutathione and coelenterazine,harvested and resuspended in Ham's F12 medium. Calcium mobilization ismeasured by monitoring luminescence provoked by calcium binding to theintracellular photoprotein aequorin. Ligands are added indimethylsulfoxide which is kept constant at 1% (v/v) in all incubations.For agonists, second messenger responses are expressed as a function ofligand concentration and both EC₅₀ values and the maximum response ascompared to a prostanoid standard are calculated. For antagonists, theability of a ligand to inhibit an agonist response is determined bySchild analysis and both K_(B) and slope values are calculated.

Prevention of PGD2 or Allergen Induced Nasal Congestion in AllergicSheep

Animal preparation: Healthy adult sheeps (18-50 kg) are used. Theseanimals are selected on the basis of a natural positive skin reaction toan intradermal injection of Ascaris suum extract.

Measurements of nasal congestion: The experiment is performed onconscious animals. They are restained in a cart in a prone position withtheir heads immobilized. Nasal airway resistance (NAR) is measured usinga modified mask rhinometry technique. A topical anaesthesia (2%lidocaine) is applied to the nasal passage for the insertion of anasotracheal tube. The maximal end of the tube is connected to apneumotachograph and a flow and pressure signal is recorded on anoscilloscope linked to a computer for on-line calculation of NAR. Nasalprovocation is performed by the administration of an aerosolizedsolution (10 puffs/nostril). Changes in the NAR congestion are recordedprior to and for 60-120 minutes post-challenge.

Prevention of PGD2 and Allergen Induced Nasal Obstruction in CynomolgusMonkey

Animal preparation: Healthy adult male cynomologus monkeys (4-10 kg) areused. These animals are selected on the basis of a natural positive skinreaction to an intradermal injection of Ascaris suum extract. Beforeeach experiment, the monkey selected for a study is fasted overnightwith water provided at libitum. The next morning, the animal is sedatedwith ketamine (10-15 mg/kg i.m.) before being removed from its homecage. It is placed on a heated table (36° C.) and injected with a bolusdose (5-12 mg/kg i.v.) of propofol. The animal is intubated with acuffed endotracheal tube (4-6 mm I.D.) and anaesthesia is maintained viaa continuous intravenous infusion of propofol (25-30 mg/kg/h). Vitalsigns (heart rate, blood pressure, respiratory rate, body temperature)are monitored throughout the experiment.

Measurements of nasal congestion: A measurement of the animalrespiratory resistance is taken via a pneumotachograph connected to theendotracheal tube to ensure that it is normal. An Ecovision accousticrhinometer is used to evaluate nasal congestion. This technique gives anon-invasive 2D echogram of the inside of the nose. The nasal volume andthe minimal cross-sectional area along the length of the nasal cavityare computed within 10 seconds by a laptop computer equipped with acustom software (Hood Laboratories, Mass, U.S.A.). Nasal challenge isdelivered directly to the animal's nasal cavity (50 μL volume). Thechanges in nasal congestion are recorded prior to and for 60-120 minutespost-challenge. If nasal congestion occurs, it will translate into areduction in the nasal volume.

Pulmonary Mechanics in Trained Conscious Squirrel Monkeys

The test procedure involves placing trained squirrel monkeys in chairsin aerosol exposure chambers. For control purposes, pulmonary mechanicsmeasurements of respiratory parameters are recorded for a period ofabout 30 minutes to establish each monkey's normal control values forthat day. For oral administration, compounds are dissolved or suspendedin a 1% methocel solution (methylcellulose, 65HG, 400 cps) and given ina volume of 1 mL/kg body weight. For aerosol administration ofcompounds, a DeVilbiss ultrasonic nebulizer is utilized. Pretreatmentperiods vary from 5 minutes to 4 hours before the monkeys are challengedwith aerosol doses of either PGD2 or Ascaris suum antigen; 1:25dilution.

Following challenge, each minute of data is calculated by computer as apercent change from control values for each respiratory parameterincluding airway resistance (R_(L)) and dynamic compliance (C_(dyn)).The results for each test compound are subsequently obtained for aminimum period of 60 minutes post challenge which are then compared topreviously obtained historical baseline control values for that monkey.In addition, the overall values for 60 minutes post-challenge for eachmonkey (historical baseline values and test values) are averagedseparately and are used to calculate the overall percent inhibition ofmediator or Ascaris antigen response by the test compound. Forstatistical analysis, paired t-test is used. (References: McFarlane, C.S. et al., Prostaglandins, 28, 173-182 (1984) and McFarlane, C. S. etal., Agents Actions, 22, 63-68 (1987).)

Prevention of Induced Bronchoconstriction in Allergic Sheep

Animal Preparation: Adult sheep with a mean weight of 35 kg (range, 18to 50 kg) are used. All animals used meet two criteria: a) they have anatural cutaneous reaction to 1:1,000 or 1:10,000 dilutions of Ascarissuum extract (Greer Diagnostics, Lenois, N.C.); and b) they havepreviously responded to inhalation challenge with Ascaris suum with bothan acute bronchoconstriction and a late bronchial obstruction (W. M.Abraham et al., Am. Rev. Resp. Dis., 128, 839-44 (1983)).

Measurement of Airway Mechanics: The unsedated sheep are restrained in acart in the prone position with their heads immobilized. After topicalanesthesia of the nasal passages with 2% lidocaine solution, a ballooncatheter is advanced through one nostril into the lower esophagus. Theanimals are then intubated with a cuffed endotracheal tube through theother nostril using a flexible fiberoptic bronchoscope as a guide.Pleural pressure is estimated with the esophageal balloon catheter(filled with one mL of air), which is positioned such that inspirationproduces a negative pressure deflection with clearly discerniblecardiogenic oscillations. Lateral pressure in the trachea is measuredwith a sidehole catheter (inner dimension, 2.5 mm) advanced through andpositioned distal to the tip of the nasotracheal tube. Transpulmonarypressure, the difference between tracheal pressure and pleural pressure,is measured with a differential pressure transducer (DP45; ValidyneCorp., Northridge, Calif.). For the measurement of pulmonary resistance(R_(L)), the maximal end of the nasotrachel tube is connected to apneumotachograph (Fleisch, Dyna Sciences, Blue Bell, Pa.). The signalsof flow and transpulmonary pressure are recorded on an oscilloscope(Model DR-12; Electronics for Medicine, White Plains, N.Y.) which islinked to a PDP-11 Digital computer (Digital Equipment Corp., Maynard,Mass.) for on-line calculation of R_(L) from transpulmonary pressure,respiratory volume obtained by integration and flow. Analysis of 10-15breaths is used for the determination of R_(L). Thoracic gas volume(V_(tg)) is measured in a body plethysmograph, to obtain specificpulmonary resistance (SR_(L)=R_(L)·V_(tg)).

The following examples are provided to illustrate the invention and arenot to be construed as limiting the scope of the invention in anymanner. In the examples, unless otherwise stated,

-   all the end products of the formula I were analyzed by NMR, TLC and    elementary analysis or mass spectroscopy;-   intermediates were analyzed by NMR and TLC;-   most compounds were purified by flash chromatography on silica gel,    recrystallization and/or swish (suspension in a solvent followed by    filtration of the solid);-   the course of reactions was followed by thin layer chromatography    (TLC) and reaction times are given for illustration only;-   the enantiomeric excess was measured on normal phase HPLC with a    chiral column: ChiralPak AD; 250×4.6 mm.

The following intermediates were prepared according to literatureprocedures or purchased from the following vendor:

-   Ethyl 2-(2-oxocyclopentyl)acetate: Acros/Fisher Scientific.-   4-fluoro-2-iodoaniline: Beugelmans, R.; Chbani, M. Bull. Soc. Chim.    Fr. 1995, 132, 306-313.

EXAMPLE 1(3R)-[4-(4-CHLOROBENZYL)-7-FLUORO-5-(METHANESULFONYL)-1,2,3,4-TETRAHYDROCYCLOPENTA[b]INDOL-3-YL]ACETICACID

Step 1: (+/−)-(7-Fluoro-1,2,3,4-tetrahydrocyclopenta[b]indol-3-yl)aceticacid ethyl ester

A solution of 10.00 g of 4-fluoro-2-iodoaniline, 6.57 g of ehtyl2-(2-oxocyclopentyl)acetate and 121 mg of p-toluenesulfonic acid in 100ml of benzene was refluxed with a Dean-Stark trap under a N₂ atmospherefor 24 h. After this time, the benzene was removed under distillation.Then, 60 ml of DMF was added and the solution was degassed before 19 mlof Hunig's base followed by 405 mg of Pd(OAc)₂ were added successively.The solution was heated to 115° C. for 3 h, then cooled to roomtemperature. To quench the reaction, 300 ml of 1 N HCl and 200 ml ofethyl acetate were added and the mixture was filtered through Celite.The phases were separated and the acidic phase was extracted twice with200 ml of ethyl acetate. The organic layers were combined, washed withbrine, dried over anhydrous Na₂SO₄, filtered through Celite andconcentrated. The crude material was further purified by flashchromatography eluting with 100% toluene to provide 5.36 g of the titlecompound as a yellow solid.

¹H NMR (acetone-d₆) δ 9.76 (br s, 1H), 7.34 (dd, 1H), 7.03 (d, 1H), 6.78(td, 1H), 4.14 (q, 2H), 3.57 (m, 1H), 2.85-2.55 (m, 5H), 2.15 (m, 1H),1.22 (t, 3H).

Step 2: (+−)-(7-Fluoro-1,2,3,4-tetrahydrocyclopenta[b]indol-3-yl)aceticacid

To a solution of 1.24 g of the ester from Step 1 in 14 mL oftetrahydrofuran (THF) at room temperature, 7 mL of MeOH followed by 7 mLof 2N NaOH were added. After 2.5 h, the reaction mixture was poured intoa separatory funnel containing ethyl acetaqte (EtOAc)/1N HCl. The phaseswere separated and the acidic phase was extracted twice with EtOAc. Theorganic layers were combined, washed with brine, dried over anhydrousNa₂SO₄ and evaporated to dryness to yield 1.08 g of a crude and unstablewaxy brown oil that was used as such in the next step (>90% purity).

¹H NMR (acetone-d₆) δ 10.90 (br s, 1H), 9.77 (br s, 1H), 7.34 (dd, 1H),7.04 (dd, 1H), 6.79 (td, 1H), 3.56 (m, 1H), 2.90-2.50 (m, 5H), 2.16 (m,1H). MS (−APCI) m/z 232.2 (M−H)⁻.

Step 3:(+/−)-(5-bromo-7-fluoro-1,2,3,4-tetrahydrocyclopenta[b]indol-3-yl)aceticacid

To a solution of 2.20 g of the acid from Step 2 (>90% purity) in 30 mLof pyridine, 6.85 g of pyridinium tribromide (90% purity) was added at−40° C. The suspension was stirred for 10 min at 0° C. and warmed toroom temperature for 30 min. Then, the solvent was removed withoutheating under high vacuum. The crude material was dissolved in 40 mL ofAcOH and 2.88 g of Zn dust was added portion wise to the cold solutionat 0° C. The suspension was stirred for 15 min at 15° C. and warmed toroom temperature for an additional 15 min. At this time, the reactionmixture was quenched by the addition of 1N HCl and this mixture waspoured into a separatory funnel containing brine/EtOAc. The layers wereseparated and the organic layer was washed with water, brine, dried overanhydrous Na₂SO₄ and concentrated. This material was used withoutfurther purification in the next step.

¹H NMR (acetone-d₆) δ 10.77 (br s, 1H), 9.84 (br s, 1H), 7.09 (m, 2H),3.60 (m, 1H), 2.95-2.65 (m, 4H), 2.56 (dd, 1H), 2.19 (m, 1H).

Step 4:(+/−)-[5-bromo-4-(4-chlorobenzyl)-7-fluoro-1,2,3,4-tetrahydrocyclopenta[b]-indol-3-yl]acetic acid

To a solution of 2.13 g of the acid from Step 3 in 10 mL of THF, asolution of diazomethane in ether was added in excess until completeconsumption of the acid as monitored on TLC. Then, the solvents wereremoved under vacuum. To a solution of the crude methyl ester thusformed in 20 mL of DMF, 539 mg of a NaH suspension (60% in oil) wasadded at −78° C. The suspension was stirred for 10 min at 0° C., cooledagain to −78° C. and treated with 1.70 g of 4-chlorobenzyl bromide.After 5 min, the temperature was warmed to 0° C. and the mixture wasstirred for 20 min. At this time, the reaction was quenched by theaddition of 2 mL of AcOH and this mixture was poured into a separatoryfunnel containing 1N HCl/EtOAc. The layers were separated and theorganic layer was washed with brine, dried over anhydrous Na₂SO₄ andconcentrated. The alkylated material was hydrolyzed using the proceduredescribed in Step 2. The crude material was further purified bytrituration with EtOAc/hexanes to yield 2.35 g of the title compound asa pale brown solid.

¹H NMR (acetone-d₆) δ 10.70 (br s, 1H), 7.31 (d, 2H), 7.18 (d, 1H), 7.06(d, 1H), 6.92 (d, 2H), 5.90 (d, 1H), 5.74 (d, 1H), 3.61 (m, 1H),3.00-2.70 (m, 3H), 2.65 (dd, 1H), 2.39 (dd, 1H), 2.26 (m, 1H). MS(−APCI) m/z 436.3, 434.5 (M−H)⁻.

Step 5:(+/−)-[5-bromo-4-(4-chlorobenzyl)-7-fluoro-1,2,3,4-tetrahydrocyclopenta[b]-indol-3-yl}acetic acid

To a solution of 2.35 g of the acid of Step 4 in 130 mL of EtOH at 80°C., was added 780 μL of (S)-(−)-1-(1-naphthyl)ethylamine. The solutionwas cooled to room temperature and stirred overnight. The salt recovered(1.7 g) was recrystallized again with 200 mL of EtOH. After filtration,the white solid salt obtained was neutralized with 1N HCl and theproduct was extracted with EtOAc. The organic layer was washed withbrine, dried over anhydrous Na₂SO₄ and concentrated. The material wasfiltered over a pad of SiO₂ by eluting with EtOAc to yield 500 mg of thetitle enantiomer as a white solid. Retention times of the twoenantiomers were respectively 7.5 min and 9.4 min [ChiralPak AD column,hexane/2-propanol/acetic acid (95:5:0.1)]. The more polar enantiomer wasin 98% ee. ee=98%; Retention time=9.4 min [ChiralPak AD column: 250×4.6mm, hexanes/2-propanol/acetic acid (75:25:0.1)]; [α]_(D) ²¹=+39.2° (c1.0, MeOH).

Step 6:(3R)-[4-(4-chlorobenzyl)-7-fluoro-5-(methanesulfonyl)-1,2,3,4-tetrahydro-cyclopenta[b]indol-3-yl}aceticacid and sodium salt

The acid from Step 5 (15.4 g) was first esterified with diazomethane.The sulfonylation was accomplished by mixing the ester thus formed with16.3 g of methanesulfinic acid sodium salt and 30.2 g of CuI (I) inN-methylpyrrolidinone. The suspension was degassed under a flow of N₂,heated to 150° C. and stirred for 3 h, then cooled to room temperature.To quench the reaction, 500 ml of ethyl acetate and 500 ml of hexaneswere added and the mixture was filtered through a pad of SiO₂ by elutingwith EtOAc. The organic phases were concentrated. The crude oil wasdissolved with EtOAc, washed three times with water one time with brine,dried over anhydrous Na₂SO₄, filtered and concentrated. The crudematerial was further purified by flash chromatography eluting with agradient from 100% toluene to 50% toluene in EtOAc to provide 14 g ofthe sulfonated ester, which was hydrolyzed using the procedure describedin Step 2. The title compound (9.8 g) was obtained as a white solidafter two successive recrystallizations: isopropyl acetate/heptanefollowed by CH₂Cl₂/hexanes.

¹H NMR (500 MHz acetone-d₆) δ 10.73 (br s, 1H), 7.57 (d, 2H, J=8.8 Hz),7.31 (m, 1H), 7.29 (m, 1H), 6.84 (d, 2H, J=8.8 Hz), 6.29 (d, 1H,J_(AB)=17.8 Hz), 5.79 (d, 1H, J_(AB)=17.8 Hz), 3.43 (m, 1H), 2.98 (s,3H), 2.94 (m, 1H), 2.85-2.65 (m, 3H), 2.42 (dd, 1H), J₁=16.1 Hz, J₂=10.3Hz), 2.27 (m, 1H). ¹³C NMR (125 MHz acetone-d₆) δ 173.0, 156.5 (d,J_(CF)=237 Hz), 153.9, 139.2, 133.7, 133.3, 130.0 (d, J_(CF)=8.9 Hz),129.6, 128.2, 127.5 (d, J_(CF)=7.6 Hz), 122.2 (d, J_(CF)=4.2 Hz), 112.3(d, J_(CF)=29.4 Hz), 111.0 (d, J_(CF)=22.6 Hz), 50.8, 44.7, 38.6, 36.6,36.5, 23.3. MS (−APCI) m/z 431.1, 434.1 (M−H)⁻.

ee=97%; Retention time=15.3 min [ChiralCel OD column: 250×4.6 mm,hexanes/2-propanol/ethanol/acetic acid (90:5:5:0.2)]; [α]_(D) ²¹=−29.3°(c 1.0, MeOH). Mp 175.0° C.

The sodium salt was prepared by the treatment of 6.45 g (14.80 mmol) ofthe above acid compound in EtOH (100 mL) with 14.80 mL of an aqueous 1NNaOH solution. The organic solvent was removed under vacuum and thecrude solid was dissolved in 1.2 L of isopropyl alcohol under reflux.The final volume was reduced to 500 mL by distillation of the solvent.The sodium salt crystallized by cooling to rt. The crystalline sodiumsalt was suspended in H₂O, frozen with a dry ice bath and lyophilizedunder high vacuum to give 6.00 g of the title compound as the sodiumsalt.

¹H NMR (500 MHz DMSO-d₆) δ 7.63 (dd, 1H, J₁=8.5 Hz, J₂=2.6 Hz), 7.47(dd, 1H, J₁=9.7 Hz, J₂=2.6 Hz), 7.33 (d, 2H, J=8.4 Hz), 6.70 (d, 2H,J=8.4 Hz), 6.06 (d, 1H, J_(AB)=17.9 Hz), 5.76 (d, 1H, J_(AB)=17.9 Hz),3.29 (m, 1H), 3.08 (s, 3H), 2.80 (m, 1H), 2.69 (m, 1H), 2.55 (m, 1H),2.18 (m, 2H), 1.93 (dd, 1H, J₁=14.4 Hz, J₂=9.7 Hz).

EXAMPLE 1A Alternative procedure for(+/−)-[5-bromo-4-(4-chlorobenzyl)-7-fluoro-1,2,3,4-tetrahydrocyclopenta[b]indol-3-yl]aceticacid (Example 1, Step 4)

Step 1: (+/−)-7-fluoro-1,2,3,4-tetrahydrocyclopenta[b]indol-3-yl)aceticacid dicyclohexylamine (DCHA) salt

A 0.526 M solution of 2-bromo-4-fluoroaniline in xylene along with ethyl(2-oxocyclopentyl) acetate (1.5 eq) and sulfuric acid (0.02 eq) washeated to reflux for 20 hours. Water was azeotropically removed with aDean-Stark apparatus. The reaction was followed by NMR and after 20hours, a 80-85% conversion to the desired imine intermediate wasgenerally observed. The reaction mixture was washed with 1M sodiumbicarbonate (0.2 volumes) for 15 minutes and the organic fraction wasevaporated. The remaining syrup was distilled under vacuum (0.5 mm Hg).Residual xylenes distilled at 30° C., then excess ketone and unreactedaniline were recovered in 50-110° C. range; the imine was recovered inthe 110-180° C. fraction as a light brown clear liquid with 83% purity.

The imine intermediate was then added to a degased mixture of potassiumacetate (3 eq), tetra-n-butylammonium chloride monohydrate (1 eq),palladium acetate (0.03 eq) and N,N-dimethylacetamide (finalconcentration of imine=0.365 M). The reaction mixture was heated to 115°C. for 5 hours and allowed to cool to room temperature. 3N KOH (3 eq)was then added and the mixture was stirred at room temperature for 1hour. The reaction mixture was diluted with water (1.0 volume), washedwith toluene (3×0.75 volume). The aqueous phase was acidified to pH 1with 3N HCl and extracted with tertbutyl methyl ether (2×0.75 volume).The combined organic fractions were washed with water (0.75 volume). Tothe clear light brown solution was added dicyclohexylamine (1 eq) andthe solution was stirred at room temperature for 16 hours. The salt wasfiltered, washed with ethyl acetate, tertbutyl methyl ether and allowedto dry to give the title compound as a tan solid. Assay: 94 A %.

1H NMR (500 mHz, CDCl3): δ 9.24 (s, 1H), 7.16-7.08 (m, 2H), 6.82 (t,1H), 6.2 (br, 2H), 3.6-3.5 (m, 1H), 3.04-2.97 (m, 2H), 2.88-2.70 (m,3H), 2.66 (dd, 1H), 2.45-2.37 (m, 1H), 2.13-2.05 (m, 2.05), 1.83 (d,4H), 1.67 (d, 2H), 1.55-1.43 (m, 4H), 1.33-1.11 (m, 6H).

Step 2:(+/−)-(5-bromo-7-fluoro-1,2,3,4-tetrahydrocyclopenta[b]indol-3-yl)aceticacid

A slurry of the DCHA salt from Step 1 above in dichloromethane (0.241 Msolution) was cooled to −20 to −15° C. Pyridine (2 eq.) was added in oneshot and to the slurry was added dropwise bromine (2.5 eq.) over 30 to45 minutes maintaining the temperature between −20° C. and −15° C. (Atabout ⅓ addition of bromine, the reaction mixture was thick and anefficient stirring was needed. Eventually, at about ½ addition ofbromine, the mixture became “loose” again.) After completion of theaddition, the reaction mixture was aged for one additional hour at −15°C. Acetic acid (3.04 eq.) was then added over 5 minutes and zinc dust(3.04 eq.) was added portion wise. (A portion of zinc was added at −15°C. and the mixture was aged for about 5 minutes to ensure that theexotherm was going (about −15° C. to −10° C.)). This operation wasrepeated with about 5 shots of zinc over about 30 min. When no moreexotherm was observed, the remaining zinc was added faster. The wholeoperation takes around 30 to 45 minutes.

After completion of the addition, the batch was warmed to roomtemperature, aged 1 hour and concentrated. The reaction mixture wasswitched to methyl t-butyl ether (MTBE, 0.8 volume) and a 10% aqueousacetic acid solution (0.8 volume) was added. The mixture(crystallization of salts, e.g pyridium) was aged at room temperaturefor 1 hour and filtered through solka-floc. The pad of solka-floc wasrinsed with MTBE (ca. 0.2 volume) and the filtrate (biphasic,MTBE/aqueous) was transferred into an extractor. The organic phase waswashed with water (0.8 volume). The MTBE extract was concentrated andswitched to isopropyl alcohol (IPA, 0.25 volume) to crystallize thecompound. water (0.25 volumes) was added and the batch was aged for 1hour. Additional water (0.33 volumes) was added over 1 hour. Aftercompletion of the water addition, the batch was aged for one additionnalhour, filtered, and rinse with 30/70 IPA/Water (0.15 volumes).Crystallized bromoacid was dried in the oven at +45° C.

Step 3:(+/−)-[5-bromo-4-(4-chlorobenzyl)-7-fluoro-1,2,3,4-tetrahydrocyclopenta[b]-indol-3-yl]aceticacid

The bromoacid of Step 2 was dissolved in dimethylacetamide (0.416 Msolution) and cesium carbonate (2.5 eq.) was added in one portion. Tothe slurry was added in one portion 4-chlorobenzyl chloride (2.5 eq.)and the batch was heated to 50° C. for 20 h. The batch was cooled tor.t. and sodium hydroxide 5N (4.00 eq.) was added over 5 minutes(temperature rises to +40° C.). The reaction was aged at 50° C. for ca.3 hours, cooled to room temperature and transferred into an L extractor.The solution was diluted with isopropylacetate (IPAc, 2 volumes) andcooled to +15° C. The solution was acidified with 5N HCl to pH˜2. Layersare separated and the organic layer was washed with water (2×2 volumes).IPAc solution was concentrated and switched to IPA (0.8 volumes) tocrystallize the product. Water (8 L) was added over 2 hours and thebatch was filtered to give the title compound in 88% isolated yield. Thebatch can be dried in the oven at +40° C. for 24 hours.

EXAMPLE 2(+/−)-{4-[1-(4-CHLOROPHENYL)ETHYL]-7-FLUORO-5-METHANESULFONYL-1,2,3,4-TETRAHYDRO-CYCLOPENTA[B]INDOL-3-YL}ACETICAICD

To a solution of 1.5 g of the methyl ester of the acid of Example 1,Step 3 (which was prepared by esterification of the corresponding acidwith diazomethane in tetrahydrofuran), 2.03 g of1-(1-bromoethyl)-4-chlorobenzene in 50 mL of acetonitrile and 6.01 g ofcesium carbonate was added. The resulting mixture was heated to refluxwith rigorous stirring for 3 hr. Then the reaction mixture was cooled toroom temperature, diluted with 50 mL of ethyl acetate, filtered, and thesolvent evaporated. The residue was purified by flash chromatography(silica gel, 4% EtOAc/hexane) to afford 1.41 g of desired N-benzylationproduct as an approximate 1:1 mixture of diastereomers according to ¹HNMR analysis.

To the above ester (1.2 g) dissolved in 80 mL of NMP, 2.63 g ofmethanesulfinic acid sodium salt and 3.7 g of Cu(I)Br was addedsuccessively. The resulting suspension was degassed under a flow of N₂,heated to 140° C. and stirred rigorously for 8 h. Then the reactionmixture was cooled to room temperature and diluted with 500 ml of ethylacetate and 500 ml of hexane. The resulting mixture was filtered througha pad of silica gel, further eluted with EtOAc. The filtrate wasconcentrated to about 300 mL of volume and washed with water and brine.The organic phase was separated and dried over anhydrous Na₂SO₄,filtered, and concentrated. The crude material was further purified byflash chromatography over silica gel eluting with 30% EtOAc/hexane toprovide 1.0 g of the sulfonated material. It was hydrolyzed to itscorresponding acid using 10 mL of 2 N NaOH in a solvent mixture composedof 10 mL of THF and 10 mL of MeOH at rt for 3 h. The reaction mixturewas neutralized with 1 M HCl aqueous solution and extracted-with EtOAc.The separated organic phase was dried over anhydrous sodium sulfate,filtered, and evaporated to afford the crude acid. The two diastereomerswere separated by using preparative BPLC (Zobax, 30% EtOAC/hexane with0.2% AcOH) to afford 300 mg of diastereomer A (shorter retention time)and 210 mg of diastereomer B (longer retention time).

Diastereomer B: ¹H NMR (acetone-d₆) δ 10.70 (br s, 1H), 7.66 (dd, 1H),7.56 (dd, 1H), 7.32 (d, 2H), 6.95 (d, 2H), 6.91 (q, 1H), 3.39 (s, 3H),3.05-3.00 (m, 1H), 2.90-2.75 (m, 2 H), 2.70 (dd, 1H), 2.44 (dd, 1H),2.43-2.34 (m, 1H), 2.21 (dd, 1H) 2.11 (d, 3H). MS (−APCI) m/z448.0(M−H)⁻.

EXAMPLE 2A Alternative synthesis of(+/−)-4-[1-(4-chlorophenyl)ethyl]-7-fluoro-5-methane-sulfonyl-1,2,3,4-tetrahydro-cyclopenta[b]indol-3-yl}acetic acid

To a solution of 6.52 g of the methyl ester of the acid of Example 1,Step 3 (which was prepared by esterification of the corresponding acidwith diazomethane in tetrahydrofuran) in 160 mL of NMP, 10.2 g ofmethanesulfinic acid sodium salt and 19 g of CuI was added successively.The resulting suspension was degassed under a flow of N₂, heated to 150°C. and stirred rigorously for 4 h. Then the reaction mixture was cooledto room temperature and diluted with 500 ml of ethyl acetate and 500 mlof hexane. The resulting mixture was filtered through a pad of silicagel, further eluted with EtOAc. The filtrate was concentrated to about300 mL of volume and washed with water and brine. The organic phase wasseparated and dried over anhydrous Na₂SO₄, filtered, and concentrated.The crude material was further purified by flash chromatography oversilica gel eluting with 30% EtOAc/hexane to provide 4.7 g of thesulfonated material, which was dissolved in 200 mL of dichloromethane.To the resulting solution, 3.39 g of 4-chlorophenyl methyl carbinol and5.68 g of triphenylphosphine was added, followed by the portion-wiseaddition of 4.99 g of di-tert-butyl azodicarboxylate. The reactionmixture was stirred at rt for 3 h and then concentrated. The residue wasloaded on a silica gel column and eluted with 5% EtOAc/hexane to afford5.1 g of methyl ester of the title compound as an approximately 1:1mixture of diastereomers according to ¹H NMR analysis. Following thehydrolysis and purification step described in Example 2, the title acidwas afforded.

EXAMPLE 3(+/−)-[9-(4-CHLOROBENZYL)-6-FLUORO-8-METHANESULFONYL-2,3,4,9-TETRAHYDRO-1H-CARBAZOL-1-YL]ACETICACID

Step 1: (+/−)-ethyl(8-bromo-6-fluoro-2,3,4,9-tetrahydro-1H-carbazol-1-yl)acetate

To a suspension of 7.24 g of (2-bromo-4-fluorophenyl)hydrazinehydrochloric acid salt in 100 mL of acetic acid, 5.5 g of ethyl2-(2-oxocyclohexyl)-acetate was added. The resulting mixture was heatedto reflux for 1 h. Then 10 mL of ethanol was added and the reactionmixture was heated at reflux overnight. The solvent was evaporated andthe residue was diluted with EtOAc and washed with saturated aqueousNaHCO₃ solution, water, and brine successively. The organic layer wasseparated and dried over anhydrous sodium sulfate, filtered, andevaporated. The residue was purified by flash chromatography over silicagel (5% EtOAc/hexane) to afford 3.12 g of desired compound.

¹H NMR (acetone-d₆) δ 9.97 (br s, 1H), 7.34 (dd, 1H), 7.13 (dd, 1H),7.09 (dd, 1H), 4.16 (q, 2H), 3.43-3.35 (m, 5H), 3.05-2.88 (m, 1H),2.76-2.53 (m, 3H), 2.10-2.00 (m, 1H), 1.96-1.87 (m, 1H), 1.82-1.72 (m,H), 1.72-1.64 (m, 1H), 1.23 (t, 3H).

Step 2:(+/−)-Ethyl[8-Bromo-9-(4-chlorobenzyl)-6-fluoro-2,3,4,9-tetrahydro-1H-carbazol-1-yl]acetate

To a solution of 3.12 g of the ester prepared in step 1 and 3.62 g of1-bromomethyl-4-chlorobenzene in 30 mL of acetonitrile, 5.74 g of cesiumcarbonate was added. The resulting mixture was stirred rigorously atreflux for 3 hr. Then it was cooled to room temperature, diluted withminimum amount of EtOAc, filtered, and evaporated. The residue waspurified by flash chromatography over silica gel (50% toluene/hexane) toafford 4.1 g of the title compound.

¹H NMR (acetone-d₆) δ 7.32 (d, 2H), 7.24 (dd, 1H), 7.13 (dd, 1H), 6.86(d, 2H), 6.00 and 5.65 (AB q, 2H), 4.15-4.05 (m, 2H), 3.44-3.35 (m, 1H),2.88-2.76 (m, 1H, 2.65-2.52 (m, 3H), 2.00-1.80 (m, 4H), 1.22 (t, 3H).

Step 3:(+/−)-[9-(4-Chlorobenzyl)-6-fluoro-8-methanesulfonyl-2,3,4,9-tetrahydro-1H-carbazol-1-yl]aceticacid

To a solution of 478 mg of the ester prepared in step 2 in 8 mL of NMP,510 mg of methanesulfinic acid sodium salt and 950 mg of CuI (I) wasadded successively. The resulting mixture was degassed under a flow ofN₂, then heated at 140° C. for 8 h under rigorous stirring. The reactionmixture was cooled to room temperature, diluted with minimum amount of a1:1 mixture of EtOAc/hexane. The resulting mixture was filtered througha pad of silica gel, further eluted with EtOAc. The filtrate wasconcentrated to about 50 mL, and washed with water and brine. Theorganic phase was collected, dried over anhydrous sodium sulfate,filtered, and evaporated. The residue was purified by flashchromatography over silica gel (30% EtOAc/hexane) to afford 320 mg ofdesired sulfonated material, which was dissolved in 5 mL of THF plus 5mL of methanol. To the resulting solution, 5 mL of 2 N of NaOH was addedand the resulting mixture was stirred at rt for 6 h. The reactionmixture was neutralized with 1 M HCl aqueous solution and extracted withEtOAc. The separated organic phase was dried over anhydrous sodiumsulfate, filtered, and evaporated. The residue was refluxed with hexaneunder rigorous stirring for 0.5 h. The resulting mixture was cooled tort under rigorous stirring, and filtered to afford 278 mg of desiredacid.

¹H NMR (500 MHz acetone-d₆) δ 10.73 (br s, 1H), 7.57 (d, 1H), 7.56 (d,1H), 7.29 (d, 1H), 6.67 (d, 2H,), 6.47 and 5.61 (AB q, 2H), 3.27-3.21(m,1H), 2.98 (s, 3H), 2.85 (dd, 1H), 2.76-2.55 (m, 3H), 2.00-1.84 (m, 3H),1.82-1.73 (m, 1H). MS (−APCI) m/z 448.0 (M−H)⁻.

EXAMPLE 4[4-(4-CHLOROBENZYL)-7-FLUORO-5-METHANESULFONYL-1-OXO-1,2,3,4-TETRAHYDROCYCLOPENTA[B]INDOL-3-YL]ACETICACID

Step 1:[5-Bromo-4-(4-chlorobenzyl)-7-fluoro-1-oxo-1,2,3,4-tetrahydro-cyclopenta[b]indol-3-yl]aceticacid methyl ester

The methyl ester of the compound of Example 1 step 5 (1.00 g, preaparedby treating the corresponding acid with excess diazomethane) in 10 mL ofa 9:1 THF/H₂O solution was treated with 2.52 g of DDQ. The reactionmixture was allowed to stir at room temperature overnight. The reactionmixture at this time was poured into a separatory funnel containingEtOAc and brine. The combined organic layers were washed with water,brine, dried over anhydrous MgSO₄ and concentrated. The resultingmaterial was further purified by flash chromatography eluting with 30%EtOAc/hexane. The chromatography procedure was repeated an additionaltwo times. 350 mg of the above ketone was obtained as a grey solid.

Step 2:[4-(4-chlorobenzyl)-7-fluoro-5-methanesulfonyl-1-oxo-1,2,3,4-tetrahydro-cyclopenta[b]indol-3-yl]aceticacid

The bromide from Step 1 (200 mg) in 4 mL of NMP was treated with 320 mgof CuI and 175 mg of CH₃SO₂Na. Nitrogen was bubbled through the reactionmixture for approximately one minute and then the mixture was heated forsix hours at 130° C. At this time the reaction mixture was cooled toroom temperature, diluted with EtOAc and filtered through a pad ofsilica gel, the residue was rinsed with additional EtOAc. The organiclayers were washed with water, brine, dried over anhydrous MgSO₄ andconcentrated. The resulting oil was purified by flash chromatographyeluting with 50% EtOAc/hexane and obtained 54 mg of the correspondingmethyl sulphone as an off-white solid.

The above methyl ester in 5 mL of THF/H₂O (1:1) and 5 mL of MeOH wastreated with 1 mL of a 1 N HCl solution. This mixture was stirred atroom temperature for two hours. At this time the reaction mixture wasacidified with a 1N HCl solution and poured into a separatory funnelcontaining water and EtOAc. The layers were separated and the aqueouslayer was extracted EtOAc. The combined organic layers were washed withwater, brine, dried over anhydrous Na₂SO₄ and concentrated. Theresulting material was further purified by flash chromatography elutingwith 100% EtOAc containing 1% AcOH and 26 mg of the title acid wasobtained as an off white solid.

¹H NMR (500 MHz, acetone-d₆) δ 11.0 (br, 1H), 7.85 (m, 1H), 7.80 (m,1H), 7.38 (d, J=8 Hz, 2H), 7.04 (d, J=8 Hz, 2H), 6.42 (d, J_(AB)=18 Hz,1H), 6.08 (d, J_(AB)=18 Hz, 1H), 3.78 (m, 1H), 3.28 (m, 1H), 3.10 (m,1H), 3.05 (s, 3H), 2.65 (m, 2H). MS (−APCI) m/z 448.2 (M−H)−.

1. A compound of the formula:

or a pharmaceutically acceptable salt thereof.
 2. A pharmaceuticalcomposition comprised of a compound in accordance with claim 1 furthercomprising a pharmaceutically acceptable carrier.
 3. A pharmaceuticalcomposition in accordance with claim 2 further comprising nicotinicacid.
 4. A compound of the formula:


5. A pharmaceutical composition comprised of a compound in accordancewith claim 4 further comprising a pharmaceutically acceptable carrier.6. A pharmaceutical composition on accordance with claim 5 furthercomprising nicotinic acid.